The present invention concerns a temperature compensated signal generator utilising a second quartz oscillator.
A signal generator with digital temperature compensation is proposed and described in the U.K. Patent Application No. 2,004,155.
Two low frequency oscillators with a frequency of 32 kHz, typical for watch circuits, are used therein having as far as possible the same quadratic temperature coefficients and different inversion temperatures. Whilst the temperature compensation can be more accurate by use of a second quartz crystal oscillator in such a circuit than with the use of other components such as capacitors, resistors or semiconductor devices, it is in the nature of low frequency quartz crystal oscillators that aging is considerable, whereby the advantage achieved is reduced in the long term.
It is therefore the object of the present invention to offer a signal generator with temperature compensation which is prone to far less aging and has higher frequency stability.